Landing flip overs. Poor Training or Poor Design?

[anthom]

After flying several different types of Gyroplanes both single seat and Dual, I have made some observations regarding the handling and general charecteristics of different gyroplanes. I will try and focus on the modern side by side Euro versions, as I have flown the Orion, Argon and recently am training someone in a Cavalon. All of them are quite benign in handling when up in the air.

While training and technique are paramount for safe flight, I feel that design charecteristics are also important to keep in mind for a safe outcome.
Despite the best training that one receives and masters, it is always possible to make a mistake, which can lead to disastrous consequences. I have found that design charecteristics may also play a significant part in a safe outcome. Sometimes mistakes in flying in a particular design can prove to be bad, while for a similar mistake in a different design, the outcome may not be as bad.

I have flown a few side by side models and have made an interesting observation. In some makes, in a side by side like the Magni and Xenon the Pilot sits in the Left seat. This to me makes sense, because the prop rotation produces a torque roll to the right. This is countered somewhat by giving a little offset for the rotor thrust at the rotor head to counter the inherent roll, but more importantly I have observed that when a single pilot is flying, the left seat is used, and it is sometimes necessary to use ballast on the right seat to adjust the lateral CG. It seems therefore obvious to me that the weight of the pilot on the left will help to offset some of the rolling moment in flight.

Not so with the Cavalon. The rotors and prop all turn in a similar direction as the others models, but the single pilot sits on the right seat.

I wonder why this is the case. To me, when there is an inherent fuselage roll tendency to the right, I feel that a single pilot on the right seat will make the rolling effect more pronounced, and this will then need to be countered by more cyclic.

Another aspect is the direction of the linked nose wheel rake, which I feel is also able to have an effect. I do not know the difference between a forward rake and a rearward rake. But I have experienced a significant nose dart effect when the nose wheel inadvertently touches the runway at speed in a take off while accelerating in the take off roll in the Cavalon versus the Orion, and more so in gusting cross winds.

What would be the effect of a nose wheel touching the runway while inadvertently landing with some forward speed? To me it is seems that a forward rake would be giving a certain amount of rotational force about the nose wheel as a pivot point, which can get accentuated if the wheel is now at an offset laterally due to the wind direction and the rudder being used.

As brought out in other threads, some designs have a high rate of flip overs, while others have none. While it is possible to say that the mistakes made may not be exactly the same, the effect to me seems that in one case there may be no flip over, while in another instance the gyroplane may flip over. It is true that differences training will help to avoid a flip over. But... even the best of the best make mistakes sometimes.

Let's take an example of a cross wind landing with strong gusting winds from the right. The rotors are still producing rotor thrust at touchdown and in this example, I would have tilted the disc to the right to counter the drift. I would also have a rudder offset, causing the linked nosewheel to be at an angle from the longitudinal axis. I inadvertently touch down with a bit of forward speed. Oops! What I have now is a fuselage with lateral CG offset to the right, rotor thrust deflected to the right, and an offset nosewheel with a forward rake. One can visualize the different forces acting that may make the machine prone to a flip over.

It seems logical to me that while I use similar landing techniques in both side by side models, I feel that one model will be prone to flip over versus the other. I have omitted the effect of a self centering nose wheel, as that is not a part of this thought process.

While the normal response of some folks may be to get better training, I also feel that it may be pertinent to look at the different design configurations that may make a difference between a safe landing and a botched one. No doubt, both are popular machines. But it is obvious that the statistics of landing accidents tell a story regarding the flip overs in Cavalons vs. Orions. Is there danger lurking in the design perhaps is my question.

Would definitely appreciate if some folks with knowledge regarding the above can help out here.

 

[Abid]

Well for sure the stats do tell a story. One is much less forgiving of this mistake than the other. Both have linked nosewheel so pouncing on linked nosewheel obviously isn't the right direction. It is the trailing front fork that helps in Orion's case as it should. It isn't rocket science. Why does AG not change its tune when even their current CEO himself decided to change the design of their initial models under his control as a UK importer ... beats me. It is most likely because they got certified that way. It is good and bad. Now you are stuck with something and to change it requires a lot of work and about the same amount of paperwork. This is the whole premise Congress created ASTM standards for. Both for LSA and now under F44 sub-committee to replace or allow in lieu of for Part 23 certification. Red tape had made making new certificated designs even simple small ones unbearable for businesses.

 

[PJB]

I think there are a few points here and some actually less of a big deal than you may first think. I'm sure that designs can be improved upon but to Abid's point in the UK it is so painful to engage that it is easier to do nothing BUT landing in a Cavalon v Magni specifically for someone with a few hours in a gyroplane is a case of 6 and 2 threes. Of course the opinion of the UK based CEO is likely to be coloured by what he finds in his home market and actually most in the UK do not overly struggle with landings.

Personally I think the lateral W&B of a Cavalon with its controls is preferable to a Magni W&B and its controls - which in my opinion are outdated.

As regard the wider question Cavalon landings tend to be less the issue than the take offs!

 

[anthom]

Personally I think the lateral W&B of a Cavalon with its controls is preferable to a Magni W&B and its controls - which in my opinion are outdated.

As regard the wider question Cavalon landings tend to be less the issue than the take offs!

Could you please elaborate a bit more on the above two. IOW, the reasons for the issues, other than a bland opinion, would be more insightful to me, who has a different perspective, based on my initial post. As I have no experience to talk of, in the Cavalon, I would like some insight into why the statistics are bad regarding the accidents.

 

[Abid]

I think there are a few points here and some actually less of a big deal than you may first think. I'm sure that designs can be improved upon but to Abid's point in the UK it is so painful to engage that it is easier to do nothing BUT landing in a Cavalon v Magni specifically for someone with a few hours in a gyroplane is a case of 6 and 2 threes. Of course the opinion of the UK based CEO is likely to be coloured by what he finds in his home market and actually most in the UK do not overly struggle with landings.

Personally I think the lateral W&B of a Cavalon with its controls is preferable to a Magni W&B and its controls - which in my opinion are outdated.

As regard the wider question Cavalon landings tend to be less the issue than the take offs!

Phil
Can you elaborate on what specifically you mean by controls of Magni being outdated? I can think of control feel as in heavy versus light, control circuit itself as in walking beans versus push-pull cable where I personally prefer walking beans and control rods and the fact that Magni as well as Xenon and it’s derivatives have a stick like a Y yoke coming out of walking beams circuit and roll is not just a sideways movement but a movement like an arc where one needs to get used to that a little bit.

The takeoff on Cavalon probably is also made more challenging by the super short couple of front and main axles and also landing not helped by its smaller track.

 

[PJB]

Could you please elaborate a bit more on the above two. IOW, the reasons for the issues, other than a bland opinion, would be more insightful to me, who has a different perspective, based on my initial post. As I have no experience to talk of, in the Cavalon, I would like some insight into why the statistics are bad regarding the accidents.

Phil
Can you elaborate on what specifically you mean by controls of Magni being outdated? I can think of control feel as in heavy versus light, control circuit itself as in walking beans versus push-pull cable where I personally prefer walking beans and control rods and the fact that Magni as well as Xenon and it’s derivatives have a stick like a Y yoke coming out of walking beams circuit and roll is not just a sideways movement but a movement like an arc where one needs to get used to that a little bit.

My view on the controls is as you say Abid - this "Y" arrangement in the M24 is a joke really and made worse because there is no roll trim adjustment once airborne and with heavy controls anyway longer flights in an M24 are frankly miserable. Of all Magni and AG product the M24 is the only one I wouldn't want to fly as a pilot and the Calidus I'd never want to be passenger in!

In terms of landing specific accidents for Cavalon in the UK they are few [actually I can't recall one at all in the UK] and certainly far fewer than take off accidents. Yet here is the issue IMO. It is harder to take a view on the generic take off/landing issues where the pilot just doesn't do what he will have been trained to do [which number a great many in my view] or a model specific issue where the landing accident is specifically because the aircraft didn't allow [or made harder] a well trained pilot to achieve the landing.

 

[nishanh]

Well for sure the stats do tell a story. One is much less forgiving of this mistake than the other. Both have linked nosewheel so pouncing on linked nosewheel obviously isn't the right direction. It is the trailing front fork that helps in Orion's case as it should. It isn't rocket science. Why does AG not change its tune when even their current CEO himself decided to change the design of their initial models under his control as a UK importer ... beats me. It is most likely because they got certified that way. It is good and bad. Now you are stuck with something and to change it requires a lot of work and about the same amount of paperwork. This is the whole premise Congress created ASTM standards for. Both for LSA and now under F44 sub-committee to replace or allow in lieu of for Part 23 certification. Red tape had made making new certificated designs even simple small ones unbearable for businesses.

Even if it's not incorporated into the official design, at least offer it as an option for the kit-builds.

 

[Abid]

My view on the controls is as you say Abid - this "Y" arrangement in the M24 is a joke really and made worse because there is no roll trim adjustment once airborne and with heavy controls anyway longer flights in an M24 are frankly miserable. Of all Magni and AG product the M24 is the only one I wouldn't want to fly as a pilot and the Calidus I'd never want to be passenger in!

In terms of landing specific accidents for Cavalon in the UK they are few [actually I can't recall one at all in the UK] and certainly far fewer than take off accidents. Yet here is the issue IMO. It is harder to take a view on the generic take off/landing issues where the pilot just doesn't do what he will have been trained to do [which number a great many in my view] or a model specific issue where the landing accident is specifically because the aircraft didn't allow [or made harder] a well trained pilot to achieve the landing.

Ok. I get what you mean.
We designed a control circuit for our side by side that does not use the Y arrangement. It does add a couple of extra connections but they are very solid and simple and we are trying to keep it where inspection of them is easy.

 

[Kevin_Richey]

Ok. I get what you mean.
We designed a control circuit for our side by side that does not use the Y arrangement. It does add a couple of extra connections but they are very solid and simple and we are trying to keep it where inspection of them is easy.

Abid: Any drawings or photos you can share here of your new SxS design?

 

[Abid]

Abid: Any drawings or photos you can share here of your new SxS design?

I have shared basic concept before but no I cannot share any more. Sorry.

 

[Vance]

Even if it's not incorporated into the official design, at least offer it as an option for the kit-builds.

In the USA with an experimental amateur built aircraft you as the builder are free to modify the aircraft any way you want.

 

[PJB]

Ok. I get what you mean.
We designed a control circuit for our side by side that does not use the Y arrangement. It does add a couple of extra connections but they are very solid and simple and we are trying to keep it where inspection of them is easy.

Yes I wish you would bring your aircraft to the UK but understand that the process to do so verse the potential market is poorly skewed.

 

[nishanh]

In the USA with an experimental amateur built aircraft you as the builder are free to modify the aircraft any way you want.

I understand that. My preference however would be for a factory or 3rd-party option rather than one of my own design.